Decoupling the Intrinsic Li/Mn Disorder Mechanism in Li-Rich Layered Oxides

Li-rich layered oxides (LLOs) are promising high-energy cathodes but suffer from irreversible oxygen redox and structural degradation associated with Li2MnO3 domains. Recently, disorder engineering has emerged as an effective strategy to regulate the local coordination environment and stabilize the oxygen redox of LLOs. Herein, we confirm the existence of intrinsic intralayer Li/Mn disorder within the Li2MnO3 domains, which can be classified into local Li-excess and TM-excess configurations derived from the initial Li-rich framework. Furthermore, DFT calculations suggest complementary local roles for the different disordered configurations: Li-excess domains promote oxygen redox activity, whereas TM-excess domains reinforce TM–O bonding and stabilize the framework against irreversible degradation. Consequently, M-LLO containing the coupled disordered configurations promotes more reversible anionic redox, suppresses irreversible oxygen release and transition-metal migration, and thereby delivers improved electrochemical stability. This work provides new insights into the role of intrinsic disorder regulation in Li-rich layered cathodes.